Sub-angstrom resolution using aberration corrected electron optics
Sub-angstrom resolution using aberration corrected electron optics
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DOI：
10.1038/nature00972
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发表时间：
2002-08-08
期刊：
影响因子：
64.8
通讯作者：
Krivanek, OL
中科院分区：
文献类型：
--
作者：
Batson, PE;Dellby, N;Krivanek, OL
20世纪30年代电子光学发明后，透镜像差将可实现的空间分辨率限制为成像电子波长的约50倍（1）。这种情况类似于列文虎克在17世纪所面临的情况。列文虎克改进玻璃透镜质量的工作直接导致他在运河水中发现了无处不在的“微生物”，这是生命细胞基础的第一个线索。电子光学像差问题从一开始就得到了很好的理解，但是在电子显微镜的实际校正方案被证明之前已经过去了60多年，即使在那时，剩余的色差仍然限制了分辨率。我们在这里报告了一个计算机控制的像差校正系统在扫描透射电子显微镜（3），这是不太敏感的色差。使用这种方法，我们实现了小于1埃的电子探针。这种性能约为120 keV能量下电子波长的20倍，允许对单个原子、几个原子的簇以及与碳基底上的Au岛共存的单个原子层原子“筏”进行动态成像。该技术还应允许使用能量低于硅损伤阈值的电子束对半导体进行原子柱成像，以检测单个掺杂剂原子。
Following the invention of electron optics during the 1930s, lens aberrations have limited the achievable spatial resolution to about 50 times the wavelength of the imaging electrons(1). This situation is similar to that faced by Leeuwenhoek in the seventeenth century, whose work to improve the quality of glass lenses led directly to his discovery of the ubiquitous "animalcules" in canal water, the first hints of the cellular basis of life. The electron optical aberration problem was well understood from the start, but more than 60 years elapsed before a practical correction scheme for electron microscopy was demonstrated 2, and even then the remaining chromatic aberrations still limited the resolution. We report here the implementation of a computer-controlled aberration correction system in a scanning transmission electron microscope(3), which is less sensitive to chromatic aberration. Using this approach, we achieve an electron probe smaller than 1 Angstrom. This performance, about 20 times the electron wavelength at 120 keV energy, allows dynamic imaging of single atoms, clusters of a few atoms, and single atomic layer 'rafts' of atoms coexisting with Au islands on a carbon substrate. This technique should also allow atomic column imaging of semiconductors, for detection of single dopant atoms, using an electron beam with energy below the damage threshold for silicon.